<My question is can it be diluted with water, and if so in what
strength, and still remain effective in killing germs?>
Isopropyl alcohol used for disinfectant normally *is* diluted to 70%
before use. In labs, I've found that it's purchased "pure" and you or a
technician make up the 70% solution yourself.
When you buy commercially prepared isopropyl alcohol, it already is a 70%
solution. No need to dilute it further.
"What you call genocide, I call a day's work!"